isRing static method
Tests whether an array of {@link Coordinate}s forms a ring, by checking length and closure. Self-intersection is not checked.
@param pts an array of Coordinates @return true if the coordinate form a ring.
Implementation
static isRing(List<Coordinate> pts) {
if (pts.length < 4) return false;
if (!pts[0].equals2D(pts[pts.length - 1])) return false;
return true;
}